1. Field of the Invention
The present invention relates generally to data transmission in a mobile communication system, and in particular, to an apparatus and method for transmitting reverse data from an MS (Mobile Station) to a BS (Base Station).
2. Description of the Related Art
A typical mobile communication system such as CDMA (Code Division Multiple Access) supports only voice service. Due to the rapid development of mobile communication technology and the growing user demands, the traditional mobile communication system has been evolved to additionally provide data service. The major examples are 1xEV-DO (1st generation Evolution-Data Only) and 1xEV-DV (1st generation Evolution-Data and Voice) developed from CDMA 2000 1x systems. Those systems aim at efficient packet data transmission using the CDMA technology of high rate data transmission. Thus appropriate scheduling is very significant in the systems.
On the forward link, a BS transmits data to only an MS at the best channel condition, taking into account the air status and other environmental conditions, thereby maximizing the data transmission throughput of the MS in the mobile communication systems. On the reverse link, a plurality of mobile stations access the BS simultaneously to transmit packet data. Therefore the BS must appropriately control the reverse data flow and congestion, thus controlling overload within the capacities of the MSs.
The 1x EV-DO system, however, has limitations in effective control of the reverse link because it controls the reverse link via a common channel. Moreover, 1x EV-DV systems under discussion are yet to be defined specifically, not to speak of their reverse link operation. While 1x EV-DV has been discussed in relation to data rate control, the data rate control simply addresses a control of bandwidth and overload without considering the statuses of mobile stations. Consequently, such a uniform control across the MSs results in serious reverse bandwidth consumption and a decrease of reverse data transmission throughput.